钟型进水流道轴流泵装置数值优化与试验分析

Numerical Optimization and Experimental Analysis of Axial-flow Pump System for Bell-type Inlet Passage

基于RNG k-ε紊流模型和雷诺时均N-S方程,运用流体计算CFD软件对钟型进水流道的轴流泵装置进行三维流动数值模拟以及水力性能的优化设计。通过先局部后整体的方法先单独对钟型进水流道进行优化,然后在整体泵装置内对弯管式出水流道进行优化,对进、出水流道进行三维参数化建模,进水流道以出口断面速度均匀度和水力损失为目标函数,出水流道以泵装置效率为目标函数,针对设计流量工况点,分别对进水流道和出水流道各控制参数方案进行数值模拟计算,分析不同控制尺寸对进、出水流道水力性能的影响。最后通过模型试验对优化方案数值计算结果进行可靠性验证。数值模拟和模型试验结果表明,优化后钟型进水流道的水力损失由0.348 m降低到0.148 m,钟型进水流道出口流速均匀度由54.59%提高到93.35%;弯管式出水流道的水力损失由0.464 m降低到0.415 m,通过优化流态得到了改善。模型泵装置试验在叶片安放角0°时,设计工况下泵装置效率达到74%,泵装置最高效率为76.47%,高效区运行范围较宽;进出水流道无漩涡产生,流态均匀,数值模拟和模型试验外特性曲线误差在5%以内,进水流道水力损失曲线趋势相同。运用数值模拟优化计算钟型进水流道的轴流泵装置,缩短了试验周期,节约了成本,可为同类泵站的设计和安全运行提供参考。

Based on the RNG k-ε turbulence model and Reynolds-averaged N-S equation,the CFD software was used to simulate the three-dimensional flow value of axial flow pump device for bell-type inlet channel and design the hydraulic performance optimization. Firstly,the bell-type inlet channel was optimized through the part to overall method,and then the elbow outlet channel of the whole pump device was optimized,three-dimensional parametric modeling can be made for the inlet and outlet flow channel.The inlet flow channel took the outlet section velocity uniformity and the hydraulic loss as the objective function. At the same time,the outlet flow channel took the pump device efficiency as the objective function. According to the design flow conditions and the control parameters numerical simulation of the inlet and outlet flow channels,the influence of different control sizes on the hydraulic performance of inlet and outlet channels can be analyzed. Finally,the reliability of the numerical results of the optimization scheme was verified by the model test. Numerical simulation and model test showed that by optimization the flow can be improved. After optimization,the hydraulic loss of the bell-type inlet channel was reduced from 0. 348 m to 0. 148 m,while the outlet velocity uniformity was increased from 54. 59% to93. 35%. Also,the hydraulic loss of the elbow-type outlet channel was reduced from 0. 464 m to0. 415 m. When the model pump device test in the blade placement angle was 0°,the design conditionsefficiency can be up to 74%. The maximum efficiency was 76. 47% and the high-efficient operating range was wide. There was no whirlpool produced in both inlet and outlet channels with uniform flow.The error of the external characteristic curve was less than 5% in the simulation and model test. The hydraulic loss curve of the inlet channel was also the same. The less hydraulic losses of the inlet and outlet flow channels after optimization, indicated that the numerical simulation involved in the optimization of the pump was reasonable and reliable. Using the numerical simulation to optimize the calculation of the axial flow pump of the bell-type inlet channel can shorten the test cycle and save the cost. It also can guide the engineering application accurately and reliably,and provide reference for the design and safe operation of the similar pump station.